Rotary motor or pump



March 19, 1963 H. NYMAN ET AL 3,081,708

ROTARY MOTOR OR PUMP Filed Aug. 10. 1960 2 Sheets-Sheet 1 FIG. I.

FIG. 2.

IN V EN TORS HUGO NY MAN BY PAUL DEVENDORF ATTORNEYS March 19, 1963 H. NYMAN ET AL ROTARY MOTOR 0R PUMP Filed Aug. 10, 1960 ATTORNEYS ilnite This invention relates to rotary motors or pumps of the type employing a plurality of radially reciprocating pistons.

In conventional devices of this type a rotor is provided with two rows of axially reciprocating pistons and each of the pistons has an outer portion which engages a rotary shell mounted eccentrically of the rotor. The pistons reciprocate as the rotor turns. A ported housing carries a fluid, usually hydraulic fluid, to and from the rotor. When hydraulic fluid is supplied through the housing inlet and discharged through the housing outlet the action of the pistons is such as to cause rotary movement of the rotor within the housingand this movement is used to drive an output shaft. Conversely, the device may be used as a pump by using the shaft to drive the rotor, thereby causing the pistons to pump fluid from one housing port to the other.

Such conventional devices as described above when employed as high speed motors operated by hydraulic fluid have given difliculty in situations where the load has been allowed to overrun the rotor shaft. In such situations it has been found that the outer ends of the radially reciprocating pistons are caused to hammer against the internal surface of the enclosing eccentric shell. The impact forces are so high that brinnelling occurs with consequent rapid wear and deterioration.

Accordingly, it is an important object of our invention to provide an improved form of rotor motor or pump in which novel means are provided to prevent such impacting action. Another object is to provide a free floating ring encircling the rotor and interposed between the rows of pistons and arranged to contact an annular shoulder on each piston. In this way, the pistons are maintained in contact with the internal surface of the shell, and turning movement of the pistons within their cylinders is permitted by rotary movement of the retainer ring relative to the rotor.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

FIGURE 1 is a top plan view showing a preferred embodiment of this invention.

FIGURE 2 is a sectional side elevation taken substantially on the lines 22 as shown in FIGURE 1.

FIGURE 3 is a transverse sectional view taken substantially on the lines 3-3 as shown in FIGURE 2.

FIGURE 4 is a transverse sectional view taken substantially on the lines 44 as shown in FIGURE 2.

FIGURE 5 is a top plan view of one of the piston heads showing the approximate area of annular contact with the enclosing shell.

Referring to the drawings, the hydraulic motor or pump generally designated includes a housing 11 formed of two parts 12 and 13 connected by threaded fastenings 14. The housing part 13 is provided with a central stationary ported support 15 and a rotor 16 is mounted to turn on this support 15. A liner 17 fixed within the bore of the rotor 16 turns on the outer surface of the stationary ported support 15.

The rotor 16 is provided with two rows of radially extending cylindrical bores 18, and a piston 19 is mounted in each of the bores 18 for both radial movement and turning movement. Each piston 19 is provided with an States Patent 0 3,fl3l,7fl8 Patented Mar. 1%, 63

integral enlarged head 20 having a convex end face 21. Each head 20 is also provided with an annular shoulder 22 and an undercut groove 22a. The end face 21 of each piston head 29 is adapted to engage the curved concave surface 23 of the cylindrical shell 24, and the area 23a of annular contact is shown diagrammatically in FIGURE 5. This shell 24 is rotatably mounted on axially spaced bearing assemblies 25 and 26 mounted within the housing 11. The rotary axis of the shell 24 is laterally offset from the rotary axis of the rotor 16, with the result that the pistons 19 reciprocate relative to the rotor 16 when the rotor and shell 24 turn within the housing 11.

Means are provided for maintaining the piston heads 20 in contact with the shell 24, and as shown in the drawings, this means comprises a hoop-like free floating ring 28 positioned between the two rows of radial cylinders 18 on the rotor 16. The path of the piston heads in one row overlying the path of the piston heads in the other row. The outer periphery of the ring 28 is cylindrical and engages the annular shoulder 22 on each of the piston heads 20, while the undercut grooves 22:: provide clearance. The ring 28 lies between the two rows of pistons and encircles a portion of the rotor 16. The ring 28 maintains each of the end faces 21 in contact with the concave surface 23 of the rotary shell 24, thus serving to eliminate hammering or impact action in the event that the load should overrun the output shaft. As will be understood by a comparison of FIGURES 3 and 4, the pistons 19 in one row are staggered with respect to the piston 1h of the other row and accordingly each is in contact with the free floating ring 2-8. This construction prevents any appreciable sidewise movement of the free floating ring 28.

The convex shape of the end faces 21 and the concave shape of the internal surface 23 of the shell 24 produce turning movement of each piston 19 within. its respective bore 18 as the rotor 16 and shell 24 turn Within the housing 11. This turning movement of the piston 19 is beneficial since it tends to spread out the wear over the entire annular area 230 on the end surfaces 21. The contact of the free floating ring 28 with the annular shoulder 22 on each piston head insures uniform turning movement of each piston 19 within its respective cylinder 18. It will be noted that pistons 19 in one row turn in one direction and that the pistons 19 in the other row turn in the other direction.

A drive member 30 is provided with a splined socket 31 which forms a driving connection with a spline shaft (not shown). The member 30 is also provided with external splines 32 at one end which form a driving connection with the internal splines 33 provided on the rotor 16. A stationary thrust ring 34 mounted on the housing, engages a spherical surface 35 on the drive member 30 to prevent axial shifting movement thereof. The drive member 30 projects through bore 36 in the nonrotary hub 37. The end surface 38 of this hub is engaged by the end surface 39 of the ring 40 which is caused to rotate with the drive member 3%) by means of the pin con nection 41. The nonrotary hub 37 is carried within bore 42 of the closure 43 which is connected to the housing part 12 by means of threaded fastenings 44.

In operation, hydraulic fluid under pressure is admitted into the housing part 13 through inlet port 5% and discharged through outlet port 51. Passageways 52 formed in the housing part 13 connect the ports 5t) and 5 1 with the openings 53 and 54, respectively, in the ported support 15, and lead to the valve chambers 55 and 56, respectively, on opposite sides of the divider 57. The rotating liner 17 and stationary ported support 15 serve as a pintle valve connecting each cylinder 18 in turn to inlet pressure and to exhaust through ports 58. The eccentric mounting of the rotary shell 24 causes rotation of the rotor 16 and shell 24 under the action of the pistons 19 reciprocating within the respective cylinders 18. The turning movement of the rotor is communicated to the drive member through the splined connection 32, 33 and the drive member 30 turns a shaft (not shown) through the internal splined socket 31. The free floating ring 28 maintains each of the piston heads 20 in contact with the rotary shell 24 and the ring 28 turns with respect to the rotor 16 as the pistons 19 turn within their respective cylinders 18.

Having fully described our invention, it is to be understood that we do not Wish to be limited to the details herein set forth, but our invention is of the full scope of the appended claims.

We claim:

1. In a rotary motor or pump, the combination of: a housing having a rotor mounted to turn therein, the rotor having two rows of radially extending cylinders, a plurality of pistons, each piston being slidably mounted for radial movement and turning movement within one of said cylinders, respectively, a shell rotatably mounted within the housing and eccentrically positioned with respect to the rotor, each of the pistons having a head fixed thereon contacting said shell, the path of the piston heads in one row overlying the path of the piston heads in the other row each piston head having an annular radial shoulder, and a free floating ring interposed between said rows of cylinders and having a cylindrical surface contacting said annular shoulders whereby the piston heads are maintained in contact with said shell.

2. In a rotary motor or pump, the combination of: a ported housing having a rotor mounted to turn therein, the rotor having two rows of radially extending cylinders, a plurality of pistons, each piston being slidably mounted for radial movement and turning movement within one of said cylinders, respectively, a shell rotatably mounted within the housing and eccentrically positioned with respect to the rotor, the shell having an internal concave surface, each of the pistons having an enlarged head fixed thereon and provided with a curved end face for contact with said shell surface, each piston head having an annular radial shoulder, a free floating ring interposed between said rows of cylinders and having a cylindrical surface contacting said annular shoulders whereby said end faces are maintained in contact with said shell surface and whereby turning movement of said pistons within said cylinders cause rotary movement of the free floating ring relative to the rotor.

3. In a rotary motor or pump, the combination of: a housing having a central stationary ported support, rotor mounted to turn on said support, the rotor having two axially spaced rows of radially extending cylinders, a plurality of pistons, each piston being slidably mounted for radial movement and turning movement within one of said cylinders, respectively, a shell rotatably mounted within the housing and eccentrically positioned with respect to the rotor, the shell having an internal concave surface, each of the pistons having an enlarged head fixed thereon and provided with a convex end face for contact with said shell surface, each head also having an annular radial shoulder, and a free floating ring encircling the rotor and interposed between said rows of cylinders, the free floating ring having an outer cylindrical periphery contacting said annular shoulders on each of the piston heads whereby said end faces are maintained in contact with said shell surface and whereby turning movement of said pistons Within said cylinders cause rotary movement of the free floating ring relative to the rotor.

4. In a rotary motor or pump, the combination of: a rotor having two rows of radially reciprocable pistons rotatably mounted thereon, a shell rotatably mounted eccentrically with respect to the rotor, the shell having an internal concave surface, each of the pistons having a head fixed thereon and provided with a convex end face contacting said shell surface, the path of the piston heads in one row overlying the path of the piston heads in the other row each piston head having an annular radial shoulder, and a free floating ring encircling said rotor between said rows of pistons and having an outer cylindrical surface contacting each of said shoulders.

5. In a rotary motor or pump, the combination of: a rotor having two rows of radially extending cylinders, pistons having portions slidably and rotatably received in said cylinders, a shell rotatably mounted eccentrically with respect to the rotor, the shell having an internal surface, each of the pistons having a head fixed thereon and projecting from its cylinder and having an end face contacting said shell surface, the path of the piston heads in one row overlying the path of the piston heads in the other row each piston head having an undercut groove and an adjacent annular radial shoulder, and a retainer ring encircling said rotor between said rows of cylinders and having a cylindrical surface contacting each of said shoulders adjacent said undercut grooves.

6. In a rotary motor or pump, the combination of: a rotor having two rows of radial reciprocable pistons mounted to rotate thereon about their individual axes, a shell rotatably mounted eccentrically with respect to the rotor and having an internal concave surface, each of the pistons having a head fixed thereon provided with a convex end face contacting said shell surface, each piston head having an annular shoulder, a free floating ring en circling said retainer between said rows of pistons and having an outer surface contacting each of said shoulders, the location of the contact of each convex end face with said concave shell surface being remote from the position of the contact of the free floating ring with the annular shoulder of each respective piston, whereby the ring rotates with respect to the rotor as the pistons reciprocate and turn about their respective axes.

References Cited in the file of this patent UNITED STATES PATENTS 1,152,729 Hele-Shaw Sept. 7, 1915 2,074,068 Ferris Mar. 16, 1937 FOREIGN PATENTS 463,854 Great Britain Apr. 7, 1935 989,135 France May 23, 1951 

1. IN A ROTARY MOTOR OR PUMP, THE COMBINATION OF: A HOUSING HAVING A ROTOR MOUNTED TO TURN THEREIN, THE ROTOR HAVING TWO ROWS OF RADIALLY EXTENDING CYLINDERS, A PLURALITY OF PISTONS, EACH PISTON BEING SLIDABLY MOUNTED FOR RADIAL MOVEMENT AND TURNING MOVEMENT WITHIN ONE OF SAID CYLINDERS, RESPECTIVELY, A SHELL ROTATABLY MOUNTED WITHIN THE HOUSING AND ECCENTRICALLY POSITIONED WITH RESPECT TO THE ROTOR, EACH OF THE PISTONS HAVING A HEAD FIXED THEREON CONTACTING SAID SHELL, THE PATH OF THE PISTON HEADS IN ONE ROW OVERLYING THE PATH OF THE PISTON HEADS IN THE OTHER ROW EACH PISTON HEAD HAVING AN ANNULAR RADIAL SHOULDER, AND A FREE FLOATING RING INTERPOSED BETWEEN SAID ROWS OF CYLINDERS AND HAVING A CYLINDRICAL SURFACE CONTACTING SAID ANNULAR SHOULDERS WHEREBY THE PISTON HEADS ARE MAINTAINED IN CONTACT WITH SAID SHELL. 